Spider dials

[MILGAUSS88]

Originally Posted by lightingball2

Can someone explain these to me? What causes the dials to do this.

Being familiar with other items that have paint over metal, I would speculate that the cracking is caused by rapid or significant changes in temperature.

I have seen a lithographed tin that had complete mint paint on it (with no cracking) when it left the midwest in sub zero temperatures, when it arrived in California and the 70-80 degree weather it had about 30% of the paint still on it.
There was no explanation for the paint loss, other than the change in temperature. Other tin litho items did not have the same fate, so apparently the different properties of paint do matter.

I would imagine the same thing could happen when wearing the watch in the cold and bringing it inside.